: Understanding the categories in terms of which people act is a basic tenet of anthropological research. This principle should apply to the study of scientists, yet analysts (social scientists and others) often do not address the content of science and, therefore, ignore a significant aspect of the conceptual framework within which scientists act. This paper examines, in the case of the development of the American secret nuclear surveillance system, the limitations of interpretations that do not adequately analyze such a conceptual framework. It also examines the implications of this case for an anthropology of science